Pain relief compounds

ABSTRACT

The present invention relates to the use of compounds for the treatment or prevention of pain in mammals, in particularly in human beings, and also to a process for preparing these compounds.

The present invention relates to compounds for the use in the treatment or prevention of pain in mammals, notably in humans, as well as a method for preparing these compounds.

Analgesics used today are old products and several of them date from the 19th century. Morphine is the reference analgesic for pains by nociception excesses.

However, morphine may be at the origin of multiple undesirable effects such as sleepiness, respiratory depression, nauseas, vomiting, convulsions, miosis, constipation or further dry mouth feeling.

Thus, the discovering of new anti-pain agents with at least equivalent effectiveness or even superior than morphine and without any undesirable effects is a major research objective for many teams worldwide.

Document WO 2011/033241 describes the use of potassium channel activators, notably TREK channels, as analgesic agents. However, the document does not give any indications for the compounds that may exhibit such an activity.

Cinnamyl 3,4-dihydroxy-α-cyanocinnamate or CDC, as well as its potential use as neuro- or cardio-protective agents, was described as an activator of TREK-1 channels (Sanjay et al., Mol. Pharmacol., 2004, 65, 599-610). However this document does not describe any analgesic activity of CDC.

Thus, a first object of the invention consists of proposing anti-pain compounds which get rid of the drawbacks of the state of the art and which provide a solution to all or part of the problems of the state of the art.

Another object is to propose anti-pain compounds for which the effectiveness for treating pain, notably pains by nociception excesses, is equivalent to, or even superior than the presently available compounds, notably morphine, while suppressing or limiting the risks of undesirable effects.

Another object of the invention is to propose anti-pain compounds which may be combined with other anti-pain agents, such as morphine, thereby reducing the risks of secondary effects related to their use.

The object of the invention is a compound of formula (A):

wherein:

-   -   R represents:         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 5-, 6- or             7-membered carbocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 5-, 6- or             7-membered heterocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 9-, 10-, 11-,             12-, 13- or 14-membered condensed carbocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 9-, 10-, 11-,             12-, 13- or 14-membered condensed heterocycle;     -   Q represents a hydrogen atom, a halogen, a C₁-C₆ alkyl group, a         C₁-C₆ alkyl-amine group, a —CN, —NR¹R², —C(O)OR¹, a —NR³C(O)OR⁴         group;     -   Q, R and the carbon atoms to which they are bounded, form a         saturated, partially or totally unsaturated, aromatic or         non-aromatic, substituted or non-substituted, carbocycle,         heterocycle, 5-, 6-, 7-, 8-, 9-, 10-, 11-, 12-, 13- or         14-membered condensed carbocycle or, 5-, 6-, 7-, 8-, 9-, 10-,         11-, 12-, 13- or 14-membered condensed heterocycle;     -   X represents O, —CH₂, S, NR¹;     -   E, identical or different, represents a group —CHG¹;     -   n represents 0, 1, 2 or 3;     -   T represents:         -   a hydrogen atom;         -   a substituted or non-substituted, branched or non-branched             C₁-C₁₂ alkyl group;         -   a group of formula -(L)_(m)-P(O)(OT¹)₂ wherein:             -   L, identical or different, represents a group —CHG², O;             -   m represents 0, 1, 2 or 3;             -   T¹ represents an hydrogen atom, a C₁-C₆ alkyl group, a                 benzyl;         -   a residue of an amino acid linked to its N-terminal             position;         -   an aryl group;         -   a C₁-C₆ alkyl-aryl group;         -   a C₁-C₆ alkyl-heterocycle group;         -   a C₂-C₆ alkenyl-aryl group;         -   a C₂-C₆ alkenyl-heterocycle group;         -   a C₂-C₆ alkynyl-aryl group;         -   a C₂-C₆ alkynyl-heterocycle group;         -   a saturated or partially unsaturated, non-aromatic,             substituted or non-substituted, 5- or 6-membered carbocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 5- or             6-membered heterocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 8-, 9- or             10-membered condensed heterocycle;     -   R¹ represents a hydrogen atom, a C₁-C₆ alkyl group;     -   R² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH;     -   R³ represents a hydrogen atom, a C₁-C₆ alkyl group;     -   R⁴ represents a hydrogen atom, a C₁-C₆ alkyl group, a C₁-C₆         alkyl-aryl group;     -   G¹ represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a group         of formula -(L¹)_(q)-P(O)(OR⁷)₂ wherein:         -   L¹, identical or different, represents O, S, CHR⁸, —NR⁸;         -   q represents 0, 1, 2, 3, 4, 5 or 6;         -   R⁷ and R⁸ independently represent a hydrogen atom or a C₁-C₆             alkyl group, a benzyl;     -   G² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a         benzyl;         as well as an isomer or a pharmaceutically acceptable salt of         this compound, for the use for the treatment and/or the         prevention of pain         excluding

-   i) cinnamyl 3-4-dihydroxy-α-cyanocinnamate (CDC),

-   ii) ethyl 3-4-dihydroxy-α-cyanocinnamate (EDHBCA),

-   iii) 2-ethylthiophenyl 3-4-dihydroxy-α-cyanocinnamate (TEDHBCA),

-   iv) N-(3′-phenylpropyl)-3,4-dihydroxybenzylidenecyanoacetamide     (Tyrphostin B46),

-   v) 1-carboxy-1-cyano-2(3,4-dihydroxyphenyl)ethylene,

-   vi) 1-carboxy-1-cyano-2-phenylethylene,

-   vii) 1-carboxy-1-carboxy-2(4-hydroxyphenyl)ethylene,

-   viii) 1-carboxy-1-cyano-2(3,4-dihydroxyphenyl)ethylene,

-   ix) 1-carboxy-1-cyano-2(4,5-dihydroxyphenyl)ethylene,

-   x) 1-carboxy-1-cyano-2(4-methoxyphenyl)ethylene,

-   xi) 1-carboxy-1-cyano-2(4-fluorophenyl)ethylene,

-   xii) 1-carboxy-1-cyano-2(4-chlorophenyl)ethylene,

-   xiii) 1-carboxy-1-cyano-2(4-hydroxy-3,5-methoxyphenyl)ethylene,

-   xiv) 1-carboxy-1-cyano-2(4-hydroxyphenyl)ethylene,

-   xv) 1-carboxy-1-cyano-2(4-formylphenyl)ethylene

-   xvi) 1-carboxy-2(4-hydroxyphenyl)ethylene,

-   xvii) compound of formula

-   xviii) compound of formula

-   xix) compound of formula

-   xx) 2-ethoxybenzene 3-4-dihydroxy-α-cinnamate (CAPE), -   xxi) 3-(3,4-dihydroxyphenyl)-2-propenoic acid, -   xxii) methyl 3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxii i) ethyl 3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxiv) lauryl 3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxv) tent-butyl 3-(3,4-di hydroxyphenyl)-2-propenoate, -   xxvi) iso-pentyl 3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxvii) butyl 3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxviii) octanyl3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxix) iso-propyl 3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxx) iso-butyl 3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxxi) benzyl 3-(3,4-dihydroxyphenyl)-2-propenoate, -   xxxii) phenethyl3-(3,4-dihydroxyphenyl)-2-propenoate.

Advantageously, R represents:

-   -   a saturated, partially or totally unsaturated, aromatic or         non-aromatic, substituted or non-substituted, 5- or 6-membered         carbocycle;     -   a saturated, partially or totally unsaturated, aromatic or         non-aromatic, substituted or non-substituted, 5- or 6-membered         heterocycle;     -   a saturated, partially or totally unsaturated, aromatic or         non-aromatic, substituted or non-substituted, 9- or 10-membered         condensed carbocycle;     -   a saturated, partially or totally unsaturated, aromatic or         non-aromatic, substituted or non-substituted, 9- or 10-membered         condensed heterocycle.

Also advantageously, Q, R and the carbon atoms to which they are bounded, form a saturated, partially or totally unsaturated, aromatic or non-aromatic, substituted or non-substituted, carbocycle, heterocycle, 5-, 6-, 7-, 8-, 9- or 10-membered condensed carbocycle or 5-, 6-, 7-, 8-, 9- or 10-membered condensed heterocycle.

Advantageously, T represents:

-   -   a residue of an amino acid, linked by its N-terminal position         and selected from the group consisting of cysteine, glycine,         lysine, phenylalanine and serine,     -   a group of formula -(L)_(m)-P(O)(OT¹)₂ wherein:         -   L, different from each other, represent a group —CHG² and a             group O with G² represents a hydrogen atom;         -   m represents 2;         -   T¹ represents a hydrogen atom;     -   a group of formula -(L)_(m)-P(O)(OT¹)₂ wherein:         -   L, different from each other, represent a group —CHG² and a             group O with G² represents a hydrogen atom;         -   m represents 2;         -   T¹ represents a benzyl;

Advantageously, G¹ represents a group of formula -(L¹)_(q)-P(O)(OR⁷)₂ wherein:

-   -   L¹, different from each other, represent O and CHR⁸;     -   q represents 2;     -   R⁷ represents a hydrogen atom or a C₁-C₆ alkyl, a benzyl;     -   R⁸ represents a hydrogen atom.

According to the invention, the compound may be a compound of formula (A), excluding

i) a compound of formula

wherein

-   -   Q⁶ represents H, —CN, —COOH     -   X⁴ represents O     -   T⁴ represents H     -   R¹³ represents H, —OH, C₁-C₂alkoxy,     -   R¹⁴ represents H, —OH, C₁-C₂alkoxy, —NO₂, tert-butyl,         iso-proline, —CH₂SMe, —OCH, —F, —Cl,     -   R¹⁵ represents H, —OH, C₁alkoxy, —NO₂, tert-butyl, iso-proline,         —CH₂SPh, —CH₂SMe,     -   R¹⁶ represents H, —OH,

ii) compound of formula

wherein

-   -   R¹⁷ represents a halogen, —CF₃, —NO₂, —NH₂, —CN,     -   R¹⁸ h represents C₁-C₈ alkyl, C₂-C₈ alkenyl, C₁-C₈ alkoxy,         —NH—(C₁-C₈)alkyl, —C(O)—(C₁-C₈)alkyl, —O—C(O)—(C₁-C₈)alkyl,         —CO₂—(C₁-C₈)alkyl, —C(O)—NH—(C₁-C₈)alkyl, —NH—C(O)—(C₁-C₈)alkyl,         with the C₁-C₈ alkyl and the C₂-C₈ alkenyl groups which may be         branched or non-branched and may be optionally substituted with         at least one group selected from a halogen, a lower alkoxy,         —NH₂, —NH—(lower alkyl), —N-(lower alkyl)₂, cycloalkyl, aryl and         a heterocycle,     -   R¹⁹ represents a halogen, a lower alkyl, a lower alkoxy, —NH₂,         —NH-(lower alkyl), —N-(lower alkyl)₂, —CF₃, —NO₂, —CN,     -   R²⁰ represents a hydrogen or lower alkyl,     -   s represents an integer ranging from 0 to 2,     -   t represents an integer ranging from 1 to 2,     -   u represents an integer ranging from 0 to 2.

According to the invention, the compound may be a compound of formulae (A1), (A2), (A3) and (A4)

wherein R, Q, X, T, T¹, R¹, R², R³, R⁴, R⁷, R⁸, G¹, G², L and L¹ are as defined for the compound of formula (A).

According to the invention, the compound may be chosen amongst the compounds of formulae (1a), (1b), (1c), (1d), (1e), (2a), (2b), (2c), (2d), (2e), (3a), (3b), (3c), (3d), (3e), (4a), (4b), (4c), (4d) or (4e):

wherein:

-   -   X and T are as defined for the compound of formula (A);     -   Q represents a hydrogen atom, a halogen, a C₁-C₆ alkyl group, a         C₁-C₆ alkyl-amine group, —CN, NR¹R², —C(O)OR¹;     -   Q¹ represents CR¹, N, NH⁺Z⁻, NH₃ ⁺Z⁻ wherein Z⁻ independently         represents a halide ion, a carboxylate ion;     -   Q² and Q³ independently represent —CR⁹R¹⁰, O, S, NR¹;     -   Q⁴ represents N, NH⁺Z⁻;     -   Q⁵ represents O, S, NR¹;     -   R¹, R⁹ and R¹⁰ independently represent a hydrogen atom, a C₁-C₆         alkyl group;     -   R², identical or different, represents a hydrogen atom, a C₁-C₆         alkyl group, —OH;     -   R⁵ and R⁶ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, a halogen, —OH, a C₁-C₆ alkoxy group, —NH₂, —NO₂, a group         of formula -(L³)_(v)-[P(O)(OR²¹)₂]_(w), wherein:         -   L³, identical or different, represents O, S, CHR²², —NR²²;         -   v represents 0, 1, 2, 3, 4, 5 or 6;         -   w represents 1 or 2;         -   R²¹ and R²² independently represent a hydrogen atom, a C₁-C₆             alkyl group, a benzyl;     -   G¹, identical or different, represents a hydrogen atom, a C₁-C₆         alkyl group, —OH, 2 adjacent G¹ groups and the carbon atoms to         which they are bounded, form an epoxide ring, a group of formula         —X²-(L¹)_(q)—P(O)(OR⁷)₂ wherein:         -   L¹, identical or different, represents O, S, CHR⁸, —NR⁸;         -   q represents 0, 1, 2, 3, 4, 5 or 6;         -   R⁷ and R⁸ independently represent a hydrogen atom, a C₁-C₆             alkyl group, a benzyl;     -   G², identical or different, represents a hydrogen atom, a C₁-C₆         alkyl group, —OH, a benzyl.

Advantageously, R⁹ and R¹⁰ represent a hydrogen atom.

According to the invention, the compound may be chosen amongst the compounds of formulae (1a), (2a), (3a) or (4a) wherein:

-   -   Q represents a hydrogen atom, —CN, —CH₂NH₃ ⁺Z⁻, —C(O)OH, —F;     -   Q¹ represents —CH, NH⁺Z⁻;     -   Z⁻ represents Cl⁻, TFA⁻;     -   X represents O, NH;     -   T represents:         -   a hydrogen atom;         -   a methyl group;         -   an ethyl group;         -   a tert-butyl group;         -   an iso-pentyl group;         -   a lauryl group;         -   a group of formula -(L)_(m)-P(O)(OT¹)₂ wherein:             -   L, identical or different, represents a group —CHG²;             -   m represents 0, 1, 2 or 3;             -   T¹ represents a hydrogen atom, a methyl, an ethyl, a                 benzyl;         -   a residue of an amino acid, linked by its N-terminal             position and selected from the group consisting of cysteine,             glycine, lysine, phenylalanine and serine;         -   a phenyl group;         -   a cyclohexyl group;         -   a group

-   -   -   a group

-   -   -   an indole group;

    -   G¹, identical or different, represents a hydrogen atom, an ethyl         group, —OH, 2 adjacent G¹ groups and the carbon atoms to which         they are bounded, form an epoxide ring, a group of formula         -(L¹)_(q)-P(O)(OR⁷)₂ wherein:         -   L¹, identical or different, represents O, S, CHR⁸, —NR⁸;         -   q represents 0, 1, 2, 3, 4, 5 or 6;         -   R⁷ and R⁸ independently represent a hydrogen atom, a methyl             group, an ethyl group, a benzyl;

    -   G², identical or different, represents a hydrogen atom C₁-C₆         alkyl group, —OH, a benzyl;

    -   R⁵ and R⁶ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, a halogen, —OH, a C₁-C₆ alkoxy group, —NH₂, —NO₂, a group         of formula -(L₂)_(v)-[P(O)(OR²¹)₂]_(w) wherein:         -   L³, identical or different, represents a group —CHR²², O;         -   v represents 0 or 1;         -   w represents 1 or 2;         -   R²¹ and R²² independently represent a hydrogen atom, a             methyl, an ethyl, a benzyl.

According to the invention, the compound may be a compound of formula (1a) wherein:

-   -   Q represents a hydrogen atom, —CN, —CH₂NH₃ ⁺TFA⁻, —C(O)OH, —F;     -   Q¹ represents —CH, NH⁺TFA⁻;     -   X represents O or NH;     -   T represents a hydrogen atom, a methyl group, an ethyl group, a         tert-butyl group, an iso-pentyl group, a lauryl group, a         cyclohexyl group, a residue of an amino acid linked by its         N-terminal position and selected in the group consisting of         cysteine, glycine, lysine, phenylalanine and serine, a group of         formula -(L)_(m)-P(O)(OT¹)₂ wherein:         -   L, identical or different, represents a group —CHG², O;         -   m represents 0, 1, 2 or 3;         -   T¹ represents a hydrogen atom, a methyl, an ethyl, a benzyl;     -   R⁵ and R⁶ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, a halogen, —OH, a C₁-C₆ alkoxy group, —NH₂, —NO₂, a group         of formula -(L³)_(v)-[P(O)(OR²¹)₂]_(w) wherein:         -   L³, identical or different, represents a group —CHR²², O;         -   v represents 0 or 1;         -   w represents 1 or 2;         -   R²¹ and R²² independently represent a hydrogen atom, a             methyl, an ethyl, a benzyl;     -   G², identical or different, represents a hydrogen atom, a         methyl, an ethyl, —OH, a benzyl.

According to the invention, the compound may be a compound of formula (2a) wherein:

-   -   Q represents a hydrogen atom, —CN;     -   Q¹ represents —CH;     -   X represents O;     -   T represents:         -   a group of formula -(L)_(m)-P(O)(OT¹)₂ wherein:             -   L represents O;             -   m represents 1;             -   T¹ represents a hydrogen, a methyl, an ethyl, a benzyl;         -   a group

-   -   -   a group

-   -   -   an indole group;

    -   G¹ represents a hydrogen atom, a methyl, an ethyl, —OH, a group         of formula -(L¹)_(q)-P(O)(OR⁷)₂ wherein:         -   L¹, identical or different, represents O, CHR⁸;         -   q represents 0, 1, 2, 3, 4, 5 or 6;

    -   R⁷ and R⁸ independently represent a hydrogen, a methyl, an ethyl         or a benzyl;

    -   R⁵ and R⁶ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, an halogen, —OH, a group of formula         -(L³)_(v)-[P(O)(OR²¹)₂]_(w) wherein:         -   L³, identical or different, represents a group CHR²², O;         -   v represents 0 or 1;         -   w represents 1 or 2;

    -   R²¹ and R²² independently represent a hydrogen atom, a methyl,         an ethyl, a benzyl.

According to the invention, the compound may be a compound of formula (3a) wherein:

-   -   Q represents —CN;     -   Q¹ represents —CH;     -   X represents O;     -   T represents a phenyl group;     -   G¹ represents a hydrogen atom, —OH, 2 adjacent G¹ groups and the         carbon atoms to which they are bounded, form an epoxide ring;     -   R⁵ and R⁶ represent OH.

According to the invention, the compound may be a compound of formula (4a) wherein:

-   -   Q represents —CN;     -   Q¹ represents —CH;     -   X represents O;     -   T represents a phenyl group;     -   G¹ represents a hydrogen atom, —OH, 2 adjacent G¹ groups and the         carbon atoms to which they are bounded, form an epoxide ring;     -   R⁵ and R⁶ represent OH.

Advantageously, the compound according to the invention is chosen amongst the compounds of formulae (1a1) to (1a20), (2a1) to (2a3), (3a1), (4a1) or (4a2):

According to the invention, the compound according to the invention is chosen amongst the compounds of formulae (1b), (2b), (3b) or (4b) wherein:

-   -   Q represents —CN, —C(O)OH, —F, —CH₂NH₃ ⁺Z⁻, wherein Z⁻         independently represents Cl⁻ or TFA⁻;     -   Q² represents —CR⁹R¹⁰, O, S;     -   X represents O or NH;     -   T represents:         -   a hydrogen atom;         -   a methyl group;         -   an ethyl group;         -   a propyl or isopropyl group,         -   a butyl or tert-butyl group;         -   a phenyl group;         -   a group

-   -   -   a group

-   -   -   an indole group;

    -   G¹ represents a hydrogen atom, an ethyl group, —OH, 2 adjacent         G¹ groups and the carbon atoms to which they are bounded, form         an epoxide ring;

    -   R⁹ and R¹⁰ independently represent a hydrogen atom, a C₁-C₆         alkyl group.

According to the invention, the compound may be a compound of formula (1b) wherein:

-   -   Q represents —CN, —CH₂NH₃ ⁺TFA⁻;     -   Q² represents O, S;     -   X represents O;     -   T represents a hydrogen atom.

Advantageously, the compound is chosen amongst the compounds of formulae (1b1), (1b2), (1b3) and (1b4)

According to the invention, the compound may be selected from the compounds of formulae (1c), (2c), (3c) or (4c) wherein:

-   -   Q represents —CN, —CH₂NH₃ ⁺Z⁻, —C(O)OH, —F;     -   Q³ represents —CR⁹R¹⁰, O, S;     -   Z⁻ is selected from Cl⁻ or TFA⁻;     -   X represents O or NH;     -   T represents:         -   a hydrogen atom;         -   a methyl group;         -   an ethyl group;         -   a propyl or isopropyl group,         -   a butyl or tert-butyl group;         -   a phenyl group;         -   a group

-   -   -   a group

-   -   -   an indole group;

    -   G¹ represents a hydrogen atom, an ethyl group, —OH, 2 adjacent         G¹ groups and the carbon atoms to which they are bounded, form         an epoxide ring;

    -   R⁹ and R¹⁰ independently represent a hydrogen atom, a C₁-C₆         alkyl group.

According to the invention, the compound may be a compound of formula (1c) wherein:

-   -   Q represents —CN;     -   Q² represents —NH;     -   X represents O;     -   T represents a hydrogen atom.

Advantageously, the compound is a compound of formula (1c1)

According to the invention, the compound may be selected from the compounds of formulae (1d) or (1e) wherein:

-   -   X represents O, —CH₂, S, NR¹;     -   Q¹ represents —CH, N, NH⁺Z⁻;     -   Q⁴ represents N, NH⁺Z⁻;     -   Z⁻ independently represents Cl⁻ or TFA⁻;     -   T represents a hydrogen atom, an ethyl group;     -   R⁵ and R⁶ represent —OH.

Advantageously, the compound is selected from the compounds of formulae (1d1) or (1e1)

The invention also concerns a method for preparing a compound of formula (A) comprising:

(i) the preparation of a compound of formula (E) by the reaction between a compound of formula (C) and a compound of formula (D),

wherein Q, X, E, T and n are as defined for the compound of formula (A);

(ii) the reaction of a compound of formula (E) with a compound of formula RCHO wherein R is as defined for the compound of formula (A), in order to form the compound of formula (A).

According to the invention, the step (i) may consist of reacting an acid of formula (C) (1 eq) and a compound of formula (D) (1.1 eq) in anhydrous dichloromethane, N,N′-dicyclohexylcarbodiimide (DCC) or 3-(diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one (DEPBT) and N,N-dimethylaminopyridine (DMAP) or N,N-disopropylethylarnine (DIPEA) at 0° C. The formed precipitate is then filtered and the filtrate is evaporated in vacuum. The residue is purified by chromatography and the compound of formula (E) is obtained.

According to the invention, the step (ii) may consist of coupling the compound of formula (E) with an aldehyde of formula RCHO in the presence of piperidine in anhydrous dichloromethane. The mixture is washed with an aqueous solution saturated with ammonium chloride and the organic phase is extracted with ethyl acetate, dried and filtered. The organic residue is purified on silica in order to obtain the compound of formula (A).

In another embodiment of the invention, step (ii) may consist of reacting a phosphonate solution of formula (E) in anhydrous tetrahydrofurane in the presence of sodium hydride at 0° C. The aldehyde of formula RCHO is added after 30 minutes. The organic mixture is extracted with ethyl acetate, dried and filtered. The residue is purified by chromatography in order to obtain the compound of formula (A).

According to the invention, the compound according to the invention is used in the treatment or the prevention of acute pains, pains by excessive nociceptive stimulations, chronic pains, neuropathic pains, visceral pains, cancer pains, pains by the dysfunction of the sympathetic system or psychic pains.

By acute pains, are meant pains triggering reactions, the finality of which is to reduce the cause thereof and to limit the consequences thereof. Acute pains are mainly short pains and only last a few seconds. Mention may notably be made for example of pains subsequent to the contact of the skin with fire or subsequent to an insect sting.

By pains by excess of nociceptive stimulations, are meant those stemming from the stimulation of nociceptors by substances released by damaged or inflamed tissues, these substances notably including extracellular protons, nucleotides, nerve growth factors, serotonin or further bradykinin. They mainly result from lesions of peripheral tissues, thereby causing an excess of painful influxes transmitted by the nervous system.

By chronic pains, are meant pains, the duration of which may be of several months, or even of several years. They may accompany inflammatory or neuropathic pathologies.

By neuropathic pains, are meant pains related to peripheral or central lesions. These pains are related to malfunction of the mechanisms for controlling nociceptive messages and may be classified according to 2 types:

-   -   peripheral neuropathic pains may be caused by medicinal         treatment, for example by alkaloids of periwinkle (vinorelbine)         used in the treatment of cancers.     -   central neuropathic pains caused by spinal or traumatic damages,         for example a lesion at the brain.         These pains may last for a long time after the repairing of the         damaged tissues and may therefore become chronic pains.

By visceral pains, are meant pains essentially with a hypernociceptive nature, which may originate in the skin area. They may be accompanied by hyperalgesia of the skin and of the deep tissues, by tonic muscular contractions and intense emotional reactions.

By cancer pains, are meant the pains which develop in a cancer context, associating both a nociception excess related to cancer development and a neuropathic component, related to dysfunction of the peripheral nervous system consecutive to lesional invasion or to treatments.

By pains by dysfunction of the sympathetic system, are meant pains expressed both as an excess of nociception, of signs suggestive of a neuropathic component but also of sympathetic perturbations.

By psychical pains, are meant pains accompanying mental pathologies, such as for example depression or schizophrenia.

Within the scope of the present invention, the compound of formula (A) may be incorporated into a pharmaceutical composition.

Thus, the object of the invention is also a pharmaceutical composition comprising a compound of formula (A) and at least one pharmaceutically acceptable carrier.

The whole of the characteristics or preferences shown for the compound of formula (A) also apply to the composition according to the invention.

By pharmaceutically acceptable carrier, is meant any solvent, dispersion medium or additives which does not produce any secondary reaction, for example an allergic reaction, in humans or in animals. The pharmaceutically acceptable carrier may notably be selected according to the administration route, for example an oral, sub-lingual, nasal, buccal, rectal or parenteral route (i.e. intravenous, sub-cutaneous, intra-dermal or intra-muscular route). The pharmaceutically acceptable carrier is preferentially selected for an oral or parenteral administration route.

The dose depends on factors such as the administration method, the nature of the pain, the age, the weight and the health condition of the patient.

Another aspect of the invention relates to a kit comprising:

-   -   a first composition comprising a compound of formula (A),     -   a second composition comprising an anti-pain agent.

The whole of the characteristics or preferences shown for the compound of formula (A) also applies to the kit according to the invention.

The anti-pain agents used in the kit according to the invention may be selected from analgesic agents of level 1 to 3 according to the classification of the World Health Organization.

Analgesics of level 1 are peripheral analgesics against weak or moderate pains, such as paracetamol, aspirin, or non-steroidal anti-inflammatories.

Analgesics of level 2 are weak central analgesics against moderate to severe pains, which may correspond to associations between analgesics of level 1 and weaker opioid analgesics, such as tradamol.

Analgesics of level 3 are strong central analgesics against very severe and stubborn pains, such as strong opioids (morphine, pethadine, dextromoramide) and antagonists (pentazocine, nalbuphine).

According to the invention, the compositions may be administered at the same time, simultaneously or extemporaneously to the patient.

Thus, the use of the kit according to the invention gives the possibility of obtaining an equivalent anti-pain effectiveness, or even greater than the one obtained by isolated administration of the anti-pain agent, while reducing the risks of secondary effects relating to their use.

The object of the invention is also a compound of formula (B)

wherein:

-   -   R represents         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 5-, 6- or             7-membrered carbocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 5-, 6- or             7-membrered heterocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 9-, 10-, 11-,             12-, 13- or 14-membrered condensed carbocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 9-, 10-, 11-,             12-, 13- or 14-membrered condensed heterocycle;     -   Q represents a hydrogen atom, —CN, —NR¹R², C₁-C₂ alkyl-amine         group;     -   X represents O, —NH;     -   E, identical or different, represents a —CHG¹ group;     -   n represents 0 or 1;     -   T represents:         -   a hydrogen atom;         -   a substituted or non-substituted, C₂-C₄ alkynyl-aryl group;         -   a branched or non-branched, substituted or non-substituted,             C₁-C₁₂ alkyl group;         -   a group of formula -(L)_(m)-P(O)(OT¹)₂ wherein:             -   L, identical or different, represents a —CHG² group, O;             -   m represents 0, 1, 2 or 3;             -   T¹ represents a hydrogen atom, a C₁-C₆ alkyl group, a                 benzyl;         -   a residue of an amino acid linked by its N-terminal             position;         -   a saturated or partially unsaturated, non-aromatic,             substituted or non-substituted, 5-, or 6-membered             carbocycle;     -   G¹ represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a group         of formula -(L¹)_(q)-P(O)(OR⁷)₂ wherein:         -   L¹, identical or different, represents O, S, CHR⁸, —NR⁸;         -   q represents 0, 1, 2, 3, 4, 5 or 6;         -   R⁷ and R⁸ independently represent a hydrogen atom, a C₁-C₆             alkyl group, a benzyl;     -   G² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a         benzyl;     -   R¹ represents a hydrogen atom, a C₁-C₆ alkyl group;     -   R² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH;         as well as an isomer or a pharmaceutically acceptable salt of         this compound; excluding

-   i) compounds of formula (B) wherein R represents an aryl group, T     represents a hydrogen atom, Q represents —CN and n represents 0,

-   ii) cinnamyl 3-4-dihydroxy-α-cyanocinnamate (CDC),

-   iii) 3-(3,4-dihydroxyphenyl)-2-propenaïc acid,

-   iv) methyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   v) ethyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   vi) lauryl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   vii) tert-butyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   viii) iso-pentyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   ix) butyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   x) octanyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   xi) iso-propyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   xii) iso-butyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   xiii) benzyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   xiv) phenethyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   xv) cyclohexyl 3-(3,4-dihydroxyphenyl)-2-propenoate,

-   xvi) ethyl 3-4-dihydroxy-α-cyanocinnamate (EDHBCA),

-   xvii) methyl 3-(4-nitrophenyl)-2-propenoate

-   xviii) methyl 3-(4-chlorophenyl)-2-propenoate,

-   xix) methyl 3-(4-bromophenyl)-2-propenoate,

-   xx) methyl 3-phenyl-2-propenoate,

-   xxi) methyl 3-(3-chlorophenyl)-2-propenoate.

According to the invention, the compound may be chosen amongst the compounds of formulae (B1), (B2), (B3), (B4) or (B5):

wherein:

-   -   R represents:         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 5-, 6- or             7-membrered carbocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 5-, 6- or             7-membrered heterocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 9-, 10-, 11-,             12-, 13- or 14-membrered condensed carbocycle;         -   a saturated, partially or totally unsaturated, aromatic or             non-aromatic, substituted or non-substituted, 9-, 10-, 11-,             12-, 13- or 14-membrered condensed heterocycle;     -   Q represents:         -   a hydrogen atom;         -   CN;         -   NR¹R² _(;)         -   a C₁-C₂ alkyl-amine group;     -   T³ represents a substituted or non-substituted aryl group;     -   T⁴ represents:         -   a branched or non-branched, substituted or non-substituted,             C₁-C₁₂ alkyl group,         -   a group of formula -(L)_(m)-P(O)(OT¹)₂ wherein:             -   L, identical or different, represents a —CHG² group, O;             -   m represents 0, 1, 2 or 3;             -   T¹ represents a hydrogen atom, a C₁-C₆ alkyl group, a                 benzyl;         -   a saturated or partially unsaturated, non-aromatic,             substituted or non-substituted, 5- or 6-membered carbocyle;     -   T⁵ represents a residue of an amino acid linked by its         N-terminal position;     -   G¹ represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a group         of formula -(L¹)_(q)-P(O)(OR⁷)₂ wherein:         -   L¹, identical or different, represents O, S, CHR⁸, —NR⁸;         -   q represents 0, 1, 2, 3, 4, 5 or 6;         -   R⁷ and R⁸ represent a hydrogen atom, a C₁-C₆ alkyl group, a             benzyl;     -   G² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a         benzyl;     -   R¹ represents a hydrogen atom, a C₁-C₆ alkyl group;     -   R² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH.

According to the invention, the compound may be a compound of formula (B1) wherein:

-   -   R represents:         -   a bis-hydroxyphenyl group;         -   an indole group;         -   a furane group;     -   Q represents:         -   CN;         -   a group CH₂—NH₃ ⁺Cl⁻, NH₃ ⁺Cl⁻.

According to the invention, the compound may be a compound of formula (B2) wherein:

-   -   R represents a bis-hydroxyphenyl group;     -   Q represents CN;     -   T³ represents a phenyl group.

According to the invention, the compound may be a compound of formulae (B3a), (B4a) or (B5a)

wherein:

-   -   Q represents a hydrogen atom, —CN, —NR¹R², a C₁-C₂ alkyl-amine         group;     -   T⁴ represents:         -   a hydrogen atom;         -   a branched or non-branched, substituted or non-substituted,             C₁-C₁₂ alkyl group;         -   a group of formula (L)_(m)-P(O)(OT¹)₂ wherein:             -   L, identical or different, represents a —CHG² group, O;             -   m represents 0, 1, 2 or 3;             -   T¹ represents a hydrogen atom, a C₁-C₆ alkyl group, a                 benzyl;         -   a saturated or partially unsaturated, non-aromatic,             substituted or non-substituted 5- or 6-membered carbocycle;         -   a residue of an amino acid linked by its N-terminal             position;     -   G¹ represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a group         of formula -(L¹)_(q)-P(O)(OR⁷)₂ wherein:         -   L¹, identical or different represents O, S, CHR⁸, —NR⁸;         -   q represents 0, 1, 2, 3, 4, 5 or 6;         -   R⁷ and R⁸ independently represent a hydrogen atom, a C₁-C₆             alkyl group, a benzyl;     -   G² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a         benzyl;     -   R⁵ and R⁶ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, a halogen, —OH, a C₁-C₆ alkoxy group, —NH₂, —NO₂, a group         of formula -(L³)_(v)-[P(O)(OR²¹)₂]_(w) wherein:         -   L³, identical or different represents O, S, CHR²², —NR²²;         -   v represents 0, 1, 2, 3, 4, 5 or 6;         -   w represents 1 or 2         -   R²¹ and R²² independently represent a hydrogen atom, a C₁-C₆             alkyl group, a benzyl;     -   R¹ represents a hydrogen atom, a C₁-C₆ alkyl group;     -   R² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH.

According to the invention, the compound may be a compound of formula (B3a) wherein:

-   -   Q represents a hydrogen atom, —CN, —NR¹R², a C₁-C₂ alkyl-amine         group;     -   T⁴ represents:         -   a hydrogen atom;         -   a tert-butyl group;         -   an iso-pentyl group;         -   a lauryl group;         -   a group of formula -(L)_(m)-P(O)(OT¹)₂ wherein:             -   L, identical or different, represents a —CHG² group, O;             -   m represents 0, 1, 2 or 3;             -   T¹ represents a hydrogen atom, a methyl, an ethyl, a                 benzyl;         -   a cyclohexyl group;     -   G² represents a hydrogen atom, C₁-C₆ alkyl group, —OH, a group         of formula -(L²)_(r)-P(O)(OR¹⁰)₂ wherein:         -   L², identical or different, represents O, S, CHR¹¹, —NR¹¹;         -   r represents 0, 1, 2, 3, 4, 5 or 6;         -   R¹⁰ and R¹¹ independently represent a hydrogen atom, a C₁-C₆             alkyl group, a benzyl;     -   R⁵ and R⁶ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, a halogen, —OH, a C₁-C₆ alkoxy group, —NH₂, —NO₂, a group         of formula -(L³)_(v)-[P(O)(OR²¹)₂]_(w) wherein:         -   L³, identical or different, represents a —CHR²² group, O;         -   v represents 0 or 1;         -   w represents 1 or 2;         -   R²¹ and R²² independently represent a hydrogen atom, a             methyl, an ethyl, a benzyl;     -   R¹ represents a hydrogen atom, a C₁-C₆ alkyl group;     -   R² represents a hydrogen atom, C₁-C₆ alkyl group, —OH.

According to the invention, the compound may be a compound of formula (B4a) wherein:

-   -   Q represents a hydrogen atom, —CN, —NR¹R², a C₁-C₂ alkyl-amine         group;     -   T⁴ represents:         -   a hydrogen atom;         -   a branched or non-branched, substituted or non-substituted             C₁-C₁₂ alkyl group;         -   a group of formula (L)_(m)-P(O)(OT¹)₂ wherein:             -   L represents O;             -   m represents 1;             -   T¹ independently represents a hydrogen atom, a methyl,                 an ethyl, a benzyl;         -   a cyclohexyl group;     -   G¹ represents a hydrogen atom, a C₁-C₆ alkyl group, —OH, a group         of formula -(L¹)_(q)-P(O)(OR⁷)₂ wherein:         -   L¹, identical or different, represents O, CHR⁸:         -   q represents 0, 1, 2, 3, 4, 5 or 6;         -   R⁷ and R⁸ independently represent a hydrogen atom, a methyl,             an ethyl, a benzyl;     -   R⁵ and R⁶ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, a halogen, —OH, a C₁-C₆ alkoxy group, —NH₂, —NO₂, a group         of formula -(L³)_(v)-[P(O)(OR²¹)₂]_(w) wherein:         -   L³, identical or different, represents a —CHR²² group, O;         -   v represents 0 or 1;         -   w represents 1 or 2;         -   R²¹ and R²² independently represent a hydrogen atom, a             methyl, an ethyl, a benzyl;     -   R¹ represents a hydrogen atom, a C₁-C₆ alkyl group;     -   R² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH.

According to the invention, the compound may be a compound of formula (B5a) wherein:

-   -   Q represents a hydrogen atom, —CN, —NR¹R², a C₁-C₂ alkyl-amine         group;     -   T⁵ represents a residue of an amino acid linked by its         N-terminal position and selected from the group consisting of         cysteine, glycine, lysine, phenylalanine and serine;     -   R⁵ and R⁶ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, a halogen, —OH, a C₁-C₆ alkoxy group, —NH₂, —NO₂, a group         of formula -(L³)_(v)-[P(O)(OR²¹)₂]_(w) wherein:         -   L³, identical or different, represents a —CHR²² group, O;         -   v represents 0 or 1;         -   w represents 1 or 2;         -   R²¹ and R²² independently represent a hydrogen atom, a             methyl, an ethyl, a benzyl;     -   R¹ represents a hydrogen atom, a C₁-C₆ alkyl group;     -   R² represents a hydrogen atom, a C₁-C₆ alkyl group, —OH.

The different objects of the invention and their embodiments will be better understood upon reading the examples which follow. These examples are given as an indication, without any limitation.

EXAMPLE 1 (E)-2-cyano-3-(3,4-dihydroxyphenyl) 3-phenylprop-2-ynyl acrylate

Under argon, iodobenzene (8.9 mmol) was solubilized in a mixture of 1,2-dimehoxythane (10 mL) and water (10 mL). Next, were successively added potassium carbonate (21.7 mmol), copper iodide (0.36 mmol), triphenylphosphine (0.72 mmol) and 10% palladium on carbon (0.02 mmol Pd) and then left with stirring for 20 mins at room temperature. Propargylic alcohol was then added and the reaction mixture was brought to 80° C. for 18 h. After cooling, the reaction mixture was filtered on Celite® and the filter evaporated in vacuum. Next, the residue was dissolved in 20 mL of ethyl acetate and 20 mL of water and the aqueous phase was extracted with ethyl acetate (3×20 mL), dried with magnesium sulfate, filtered and evaporated in vacuum. The crude product is purified on silica (10% cyclohexane ethyl acetate) and the alcohol is isolated (99%) in the form of a colorless oil. ¹H NMR (400 MHz, CDCl₃): δ 7.59-7.24 (m, 5H), 4.52 (s, 2H), 2.12 (se, 1H).

Under argon, cyanoacetic acid (1.0 mmol) and the alcohol (0.8 mmol) were solubilized in 4 mL anhydrous dichloromethane and N,N′-dicyclohexylcarbodiimide (1.0 mmol) and N,N-dimethylaminopyridine (cat.) were successfully added at 0° C. After total consumption of the acid (CLC), the formed white precipitate was filtered and the filtrate evaporated in vacuum. The residue was purified on silica, (SiO₂, 20% ethyl acetatecyclohexane) and the ester was obtained as a colorless oil (52%). ¹H NMR (400 MHz, CDCl₃): δ 7.64-7.28 (m, 5H), 5.06 (s, 2H), 3.57 (s, 2H).

Under argon, 3,4-dihydroxybenzaldehyde (0.45 mmol) and piperidine (cat.) were added on the 3-phenylprop-2-ynyl 2-cyanoacetate (0.45 mmol) solubilized in 4 mL of anhydrous dichloromethane. Next, at room temperature the reaction mixture was stirred until total consumption of the 3-phenylprop-2-ynyl 2-cyanoacetate (TLC). After adding an aqueous solution saturated with magnesium chloride, the organic phase was extracted with ethyl acetate (3×8 mL), dried with magnesium sulfate and filtered. After evaporation in vacuum of the solvent, the residue was purified on silica (SiO₂, 30% ethyl acetatecyclohexane) and the (E-2-cyano-3-(3,4-dihydroxyphenyl) 3-phenylprop-2-ynyl acrylate ester was obtained in the form of a pale yellow solid (40%). ¹H NMR (400 MHz, MeOD-d₄): δ 8.17 (s, 1H), 7.69-7.27 (m, 8H), 5.14 (s, 2H). HR-ESI-MS calculated for C₁₉H₁₃NO₄ (M+Na⁺)=342.0732; found 342.0742.

EXAMPLE 2 (E)-2-cyano-3-(furan-3-yl) acrylic acid

Under argon, the cyanoacetic acid (7.05 mmol) was dissolved in anhydrous dichloromethane (10 mL); t-butanol (7.76 mmol), N,N′-dicyclohexylcarbodiimide (7.05 mmol) were added at room temperature. After one hour, the precipitate was filtered in vacuum and the filtrate evaporated in vacuum. The residue was purified on silica (SiO₂, 10% ethyl acetatecyclohexane) and a t-butyl ester was obtained in the form of a colorless oil (61%). ¹H NMR (400 MHz, CDCl₃): δ: 3.39 (s, 2H), 1.51 (s, 9H).

Under argon, the 3-furaldehyde (2.34 mmol) and the piperidine (cat.) were added on the butyl ester (2.12 mmol) solubilized in 15 mL of anhydrous dichloromethane. Mixed at room temperature, the reaction mixture was stirred until total consumption of the ester (TLC). After adding an aqueous solution saturated with ammonium chloride, the aqueous phase was extracted with ethyl acetate (3×8 mL), dried with magnesium sulfate and filtered. After evaporation in vacuum of the solvent, the residue was purified on silica (eluent: cyclohexane and ethyl acetate) and the alkene was obtained as a yellow powder (45%). ¹H NMR (400 MHz, CDCl₃): δ 8.03 (s, 1H), 8.02-7.23 (m, 3H), 1.56 (se, 9H).

Under argon, the alkene (0.29 mmol) was solubilized in (1 mL). After 1 h 30 mins of stirring at room temperature, the trifluoroacetic acid was evaporated in vacuum. The residue was triturated with ether and the ether was then evaporated in vacuum. The experiment was repeated 3 times and (E)-2-cyano-3-(furan-3-yl) acrylic acid as a pale yellow powder (90%) was obtained. ¹H NMR (400 MHz, MeOD-d₄): δ 8.28 (s, 1H), 8.26 (s ¹H, 1H), 7.73 (m, 1H), 7.27 (d, J=1.9 Hz, 1H). HR-ESI-MS calculated for C₈H₅NO₃ (M+Na⁺)=186.0167; found 186.0170.

EXAMPLE 3 6.7-dihydroxy-1H-indole-2-carboxylic acid

DL-DOPA (5 mmol) was solubilized in water (500 mL). After 5 mins of stirring at room temperature, a solution of potassium ferricyanide (20 mmol) in 60 mL of water was added. Next, a 1 M soda aqueous solution was added until pH=13. After 20 mins of stirring under argon, the reaction mixture was acidified with a 6 M hydrochloric acid aqueous solution until pH=2 and the aqueous phase was extracted with ethyl acetate (3×100 mL). The collected organic phases were dried and filtered in vacuum and a pale brown solid was obtained and washed with a saline solution containing 1 mmol of Na₂S₂O₅ and then with a saline solution (2×100 mL). The organic phase was dried with magnesium sulfate, filtered and evaporated in vacuum. The residue was purified on silica (SiO₂, 90% ethyl acetate methanol) and 6,7-dihydroxy-1H-indole-2-carboxylic acid was obtained as a pale brown powder. ¹H NMR (400 MHz, MeOD-d₄): δ 6.95 (s, 1H); 6.93 (s, 1H); 6.82 (s, 1H).

EXAMPLE 4 (E)-2-carboxy-3-(3,4-dihydroxyphenyl)prop-2-en-1-ammonium chloride

Triethylphosphonoacetate (44.62 mmol) was added to a methanol solution (108 mL) containing paraformaldehyde (89.24 mmol) and piperidine (4.46 mmol). After 24 hours of refluxing, the solvent was evaporated in vacuum and the primary alcohol was obtained. The residue was solubilized in toluene (60 ml), treated with para-toluenesulfonic acid monohydrate (4.46 mmol) and the reaction mixture was refluxed in a Dean-Stark setup. After 16 h, the mixture was concentrated in vacuum and distilled under reduced pressure in order to obtain vinyl phosphonate as a pale yellow oil (92%). ¹H NMR (400 MHz, CDCl₃): δ 6.82 (dd, J=2 Hz and J_(H-P)=41.9 Hz, 1H), 6.62 (dd, J=2 Hz and J_(H-P)=20.9 Hz, 1H), 4.18 (m, 6H), 1.36 (m, 3H), 1.33 (m, 6H).

A solution of t-butoxycarbonylamine (5.08 mmol) in anhydrous tetrahydrofurane (7 ml) was added, with stirring, dropwise, to a suspension of sodium hydride (50% in the oil, 9.30 mmol) in anhydrous tetrahydrofurane (15 mL) under argon at 0° C. The reaction mixture was stirred for 30 mins at 0° C. and a solution of ethyl 2-diethoxyphosphoryl acrylate (4.23 mmol) in anhydrous tetrahydrofurane (7 mL) was added. The reaction was stirred for 1 h at room temperature. Water (20 mL) was then added to the reaction mixture. The latter was acidified to pH 5 with a 1 M hydrochloric acid aqueous solution. The aqueous phase was extracted with ethyl acetate (3×30 mL), dried with magnesium sulfate and evaporated in vacuum. Finally, the residue was purified by column chromatography (70% ethyl acetate/cyclohexane) in order to obtain the ethyl 3-t-butoxycarbonylamino-2-diethoxyphosphoryl-3-propionate as a colorless oil (62%). ¹H NMR (400 MHz, CDCl₃): δ 5.10 (se, 1H), 4.15 (m 6H), 3.60 (m, 2H), 3.26 (td, J=23.0, 7.0 Hz, 1H), 1.40 (se, 9H), 1.33 (m, 6H), 1.25 (t, J=7.0 Hz, 3H).

Under argon, a solution of ethyl 3-t-butoxycarbonylamino-2-diethoxyphosphoryl-3-propionate (6.56 mmol) in anhydrous tetrahydrofurane (11 mL) was added dropwise on sodium hydride (50% in a mineral oil, 9.2 mmol) suspended in anhydrous tetrahydrofurane (11 mL) at 0° C.

The reaction mixture was stirred for 30 mins at 0° C. and then 3,4-bis(methoxymethoxy)benzaldehyde (5.05 mmol) was solubilized in anhydrous tetrahydrofurane (11 mL) which is added dropwise. After full consumption of the aldehyde (TLC), the reaction was stopped with water. The aqueous phase was extracted with ethyl acetate (3×20 mL), dried with magnesium sulfate and filtered. After evaporation in vacuum of the solvent, the residue was purified on silica by column chromatography (20% ethyl acetate cyclohexane) and the alkene (E) was obtained as a colorless oil (60%). ¹H NMR (400 MHz, CDCl₃): δ 7.69 (s, 1H), 7.15-7.33 (m, 3H), 5.25 and 5.28 (2×s, 4H), 5.8 (se, 1H), 4.26 (q, J=7.0 Hz, 2H), 4.20 (d, J=7.0 Hz, 2H), 3.50 (s, 6H), 1.42 (se, 9H), 1.30 (t, J=7.0 Hz).

The alkene E (0.642 mmol) was solubilized in methanol (2.5 mL) and then a 1M aqueous solution of lithium hydroxide (1.92 mmol) was added. After full consumption of the ester (TLC), the solvent was evaporated in vacuum. The aqueous phase was treated with a 1 M hydrochloric acid aqueous solution down to pH =2. Next, the aqueous phase was extracted with ethyl acetate (3×10 mL), dried with magnesium sulfate and filtered. After evaporation of the solvent in vacuum, the desired acid (91%) is obtained. ¹H NMR (400 MHz, CDCl₃): δ 7.69 (s, 1H), 7.15-7.33 (m, 3H), 5.25 and 5.28 (2×s, 4H), 5.8 (se, 1H), 4.20 (d, J=7.0 Hz, 2H), 3.50 (s, 6H), 1.42 (se, 9H).

To a solution of (E)-3-(3,4-bis(methoxymethoxy)phenyl)-2-((t-butoxy-carbonyl-amino)-methyl) acrylic acid (0.25 mmol) in methanol (50 mL) was added a 10% hydrochloric acid aqueous solution (10 mL). The reaction mixture was stirred for 2 days at room temperature. Next, the solvent was evaporated in vacuum and the residue was dissolved in 2 mL of dichloromethane and then methanol was added, causing precipitation of the compound. The precipitate was filtered under reduced pressure and (E)-2-carboxy-3-(3,4-dihydroxyphenyl)prop-2-en-1-ammonium chloride was obtained as a white powder (40%). ¹H NMR (400 MHz, DMSO-d₆): δ 13.00 (s, 1H), 9.71 (se, 1H), 9.28 (se, 1H), 8.13 (se, 3H), 7.73 (s, 1H), 6.99 (d, J=1.7 Hz, 1H), 6.87 (d, J=1.7 Hz, 1H), 6.86 (dd, J=8.0, 1.7 Hz, 1H), 3.84 (se, 2H). HR-ESI-MS calculated for C₁₀H₁₂NO₄(M+H⁺)=210.0766; found 210.0776.

EXAMPLE 5 (Z)-2-fluoro-3-phenylacrylic acid

To a freshly distilled solution of diisopropylamine (19.3 mmol) in anhydrous tetrahydrofurane (8 mL) was added 1.6 M n-butyl lithium (18.8 mmol) at −30° C. The solution was stirred for 30 mins at −30° C. It was then transferred into a solution consisting of ethyl 2-fluoroacetate (4.7 mmol) and of trimethylsilyl chloride (28.3 mmol) in 45 mL of anhydrous tetrahydrofurane, at −78° C. The reaction mixture was stirred and then left to return to 0° C. over a period of 4 h. The reaction mixture was treated with a saturated sodium carbonate solution (100 mL) at 0° C. The aqueous phase was extracted with ether (3×50 mL). The organic phase was dried on magnesium sulfate, filtered and then concentrated (20 mL). It was washed with a tartaric solution (50 mL) and stirred for 12 h at room temperature. The aqueous phase was extracted twice with ether (2×20 mL). The organic phases are collected and dried with magnesium sulfate and concentrated under reduced pressure. The residue was purified by chromatography (SiO₂, 10% diethyl ether/pentane) in order to lead to ethyl 2-fluoro-2-(trimethylsilyl)acetate as a colorless oil (800 mg, 95%). EI-MS (70 eV) mz: 178. ¹H NMR (400 MHz, CDCl₃): δ 4.95 (d, J=48.1 Hz, 1H), 4.20 (q, J=7.0 Hz, 2H), 1.28 (t, J=7.0 Hz, 3H), 0.18 (s, 9H).

To a freshly distilled solution of diisopropylamine (2.57 mmol) in anhydrous tetrahydrofurane (13 mL) was added a 1.6 M solution de n-BuLi (2.57 mmol) à −30° C.). La solution was stirred for 30 mins at −30° C. and then cooled to −78 ° C. Ethyl 2-fluoro-2-(trimethylsilyl)acetate (2.25 mmol), dissolved in anhydrous tetrahydrofurane (2 mL) was added to the formed LDA solution and the stirred for 40 mins at −78 ° C. followed by the addition of a solution of benzaldehyde (2.31 mmol) in anhydrous tetrahydrofurane (2 mL). The solution was brought to −78 ° C. until total disappearance of ethyl 2-fluoro-2-(trimethylsilyl)acetate (tracked by GC-MS). The reaction mixture was treated with a saturated solution of ammonium chloride (30 mL) at 0° C. The aqueous phase was extracted with ethyl acetate (3×20 mL). The collected organic phases are dried with magnesium sulfate and then concentrated under reduced pressure. The residue was purified by silica gel chromatography (5% ethyl acetatecyclohexane) so as to lead to ethyl (Z)2-fluoro-3-phenylacrylate as a colorless oil (216.7 mg, 50%). EI-MS (70 eV): mz=194. ¹H NMR (400 MHz, CDCl₃): δ 7.65-7.31 (m 5H), 6.92 (d, J=35.2 Hz, 1H), 4.36 (q, J=7 Hz, 2H), 1.40 (t, J=7 Hz, 3H).

The ester (1.12 mmol) was solubilized in methanol and a 1.5 M soda aqueous solution (2.23 mmol) is then added. After a full consumption of the ester (TLC), the solvent was evaporated in vacuum. The aqueous phase was treated with a 1M hydrochloric acid solution down to pH=2. Next, the aqueous phase was extracted with ethyl acetate (3×10 mL), tried with magnesium sulfate and filtered. After evaporation of the solvent in vacuum, the (Z)-2-fluoro-3-phenylacrylic acid was obtained as a white solid (91%). ¹H NMR (400 MHz, CDCl₃): δ 8.75 (se, 1H), 7.67-7.38 (m, 5H), 7.07 (d, J=34.6 Hz, 1H). HR-ESI-MS calculated for C₉H₆O₂F (M−H⁺)=165.0352; found 165.0341

EXAMPLE 6 (E)-2-cyano-3-(1H-indol-2-yl)acrylic acid

Sulfuric acid (248 μL) was added to a solution of indole-2-carboxylic acid (2.48 mmol) in absolute ethanol (8 mL). The reaction mixture was refluxed for 15 h, and sulfuric acid (248 μL) was added. The reaction mixture was heated for a further 3 h. After cooling to room temperature, the solvent was evaporated under reduced pressure, the residue was dissolved in 10 mL of DCM, and the resulting solution was washed with a saturated sodium carbonate aqueous solution (3×20 mL), water (10 mL) and brine (10 mL). The organic phase is dried with magnesium sulfate, filtered, evaporated under reduced pressure in order to obtain a white powder (365.8 mg, 77%). ¹H NMR (400 MHz, CDCl₃): δ 8.93 (s, 1H), 7.70 and 7.43 (2×d, J=8.1 Hz, 2H), 7.36-7.24 (m, 2H), 7.16 (t, J=7.3 Hz, 1H), 4.42 (q, J=7.1 Hz, 2H), 1.42 (t, J=7.1 Hz, 3H). A solution of ethyl 1H-indole-2-carboxylate (2.65 mmol) in anhydrous tetrahydrofurane (10 mL) was added dropwise to a cooled solution (0° C.), a lithium aluminium hydride (3.98 mmol) suspension in anhydrous tetrahydrofurane (10 mL) and the mixture was stirred for 2 h. The reaction was stopped by dropwise addition of (5 mL) and washed with water (20 mL). The organic phase was dried with magnesium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (SiO₂, 40% ethyl acetate cyclohexane) in order to obtain a white powder (386.7 mg, 99%). ¹H NMR (400 MHz, CDCl₃): δ 8.38 (se, 1H), 7.61 and 7.37 (2×d, J=8.0 Hz, 2H), 7.21 and 7.13 (m, 2H), 6.43 (t, J=7.3 Hz, 1H), 4.84 (se, 2H), 1.93 (se, 1H).

(1H-indol-2-yl) methanol (2.63 mmol) was dissolved in anhydrous tetrahydrofurane (40 mL) and treated with manganese oxide (30.24 mmol). After stirring for 18 h at room temperature, the reaction mixture was filtered and the filtrate concentrated under reduced pressure in order to obtain a brown powder (302 mg, 79%). ¹H NMR (400 MHz, CDCl₃): δ 9.86 (s, 1H), 9.30 (se, 1H), 7.76 and 7.48 (2×d, J=8.1 Hz, 2H), 7.40-7.19 (m, 2H), 7.29 (s, 1H).

Under argon, cyanoacetic acid (7.05 mmol) was dissolved in anhydrous dichloromethane (10 mL); t-butanol (7.76 mmol) and N,N′-dicyclohexylcarbodiimide (7.05 mmol) are added at room temperature. After 1 h, the precipitate formed was filered and the filtrate evaporated in vacuum. The residue was purified on silica (SiO₂, 10% ethyl acetate cyclohexane) and the t-butyl ester is obtained as a colorless oil (61%). ¹H NMR (400 MHz, CDCl₃): δ: 3.39 (s, 2H), 1.51 (s, 9H).

Under argon, indole-2-carbaldehyde (1.91 mmol) and piperidine (cat.) are added on t-butyl 2-cyanoacetate (1.91 mmol) solubilized in 4 mL of anhydrous dichloromethane. Next, at room temperature, the reaction mixture was stirred until t-butyl 2-cyanoacetate was fully consumed (TLC). After adding a saturated ammonium chloride solution, the aqueous phase was extracted with ethyl acetate (3×8 mL), dried with magnesium sulfate and filtered. After evaporation in vacuum of the solvent, the residue was purified on silica (SiO₂, 30% ethyl acetate/cyclohexane) and the ester is obtained as a yellow solid (69%). ¹H NMR (400 MHz, CDCl₃): δ 9.50 (se, 1H), 8.09 (s, 1H), 7.67 and 7.46 (2×d, J=8.1 Hz, 2H), 7.42-7.17 (m, 3H,), 1.59 (se, 9H).

Under argon, the t-butyl ester (0.74 mmol) was solubilized in trifluoroacetic acid (3 mL). After 1 h 30 mins of stirring at room temperature, trifluoroacetic acid was evaporated in vacuum. The residue was triturated with ether followed by evaporation of the latter. The experiment was repeated 3 times and (E)-2-cyano-3-(1 H-indol-2-yl)acrylic acid was obtained as a pale yellow solid (78%). ¹H NMR (400 MHz, MeOD-d₄): δ 11.17 (se, 1H), 8.27 (s, 1H), 7.68 and 7.46 (2×d, J=8.2 Hz, 2H), 7.65 (s, 1H), 7.32 and 7.12 (2×t, J=7.5 Hz, 2H). HR-ESI-MS calculated for C₁₂H₈N₂O₂ (M−H⁺)=211.0508; found 211.0514.

EXAMPLE 7 (E)-tert-butyl 3-(4-(bis(benzyloxy)phosphoryloxy)phenyl)-2-cyanoacrylate

Under argon, N-chlorosuccinimide (1.05 mmol) was dissolved in anhydrous toluene (5 mL), and then benzyl phosphite (0.95 mmol) was added. The reaction mixture was stirred for 2 hours at room temperature, and then filtered in order to remove the precipitate. The thereby obtained filtrate was concentrated under reduced pressure in order to obtain dibenzylphosphorochloridate as a colorless oil (95%).

¹H NMR (400 MHz, CDCl₃): δ 7.35 (bs, 10H), 5.25 (m, 4H).

Under argon, cyanoacetic acid (7.16 mmol) and t-butanol (6.51 mmol) are dissolved in anhydrous dichloromethane (30 mL) and cooled to 0° C. DCC (7.16 mmol) and DMAP (cat.) are added to the solution. The medium is stirred for 4 hours at 0° C. and 1 h at room temperature. The reaction mixture is filtered, then concentrated under reduced pressure. The thereby obtained is purified by column chromatography (SiO₂, 20% EtOAccyclohexane) in order to obtain the t-butyl ester as a colorless oil (86%).

¹H NMR (400 MHz, CDCl₃): δ 4.23 (q, J=6.5 Hz, 2H, H-3), 3.44 (s, 2H, H-2), 1.28 (t, J=6.5 Hz, 3H, H-4).

Under argon, 4-hydroxybenzaldehyde (0.53 mmol) and piperidine (cat.) were added to the t-butyl ester (0.53 mmol) solubilized in anhydrous dichloromethane. Next, the reaction mixture was stirred, at room temperature, until the ester is totally consumed (TLC). After adding a saturated ammonium chloride aqueous solution, the organic phase was extracted with ethyl acetate (3×8 mL), dried with magnesium sulfate and filtered. After evaporation in vacuum of the solvent, the residue was purified on silica (eluent: cyclohexane and ethyl acetate) in order to obtain the compound (E)-tert-butyl 2-cyano-3-(4-hydroxyphenyl)acrylate as a brown powder (71%).

¹H NMR (400 MHz, MeOD-d₄): δ 8.13 (s, 1H, H-3), 7.96 (m, 2H, H-2′ and H-6′), 6.93 (m, 2H, H-3′ and H-5′), 1.58 (s, 9H, 3×CH₃).

Under argon, to a solution of (E)-tert-butyl 2-cyano-3-(4-hydroxyphenyk)acrylate (0.41 mmol) in acetonitrile (2 mL), were successively added at room temperature, dibenzyl chlorophosphonate (0.61 mmol) and then potassium carbonate (1.64 mmol). The reaction mixture was stirred for 5 days, and then treated by adding an aqueous solution. The aqueous phase was extracted with ethyl acetate (3×8 mL), dried with magnesium sulfate and filtered. After evaporation in vacuum of the solvent, the residue was purified on silica (SiO₂, EtOAccyclohexane) and the compound is obtained as a colorless oil (20%). ¹H NMR (400 MHz, CDCl₃): δ 8.09 (s, 1H), 7.90 (d, J=8.8 Hz, 2H), 7.38-7.29 (m, 10H), 7.21 (d, J=8.3 Hz, 2H,), 5.13 (d, J_(P,H)=10.5 Hz, 4H), 1.59 (s, 9H).

EXAMPLE 8 Evaluation of the Activation of TREK-1 Channels bt the Compounds According to the Invention

Xenope ovocytes without their follicle cells are injected with 50 ng of cRNA coding for the TREK-1 channel.

18-24 h after injection, the TREK-1 currents are recorded with the double electrode technique. In a perfusion chamber of 0.3 mL, the ovocyte is impaled with two standard microelectrodes (resistance 1-2.5 M) filled with a 3M KCl solution and maintained at an imposed voltage by means of a Dagan TEV 200 amplifier in a ND96 standard solution (96 mM NaCl, 2 mM KCl, 1.8 mM CaCl₂, 2 mM MgCl₂, 5 mM HEPES, pH 7.4 with NaOH) for 3 mins. And then a solution of the compound (20 nM) is perfused for 15 minutes, followed by rinsing with ND96 for 6 minutes. Stimulation of the preparation, data acquisition and analyses are carried out by using the software package pClamp.

-   -   The results are shown in Table 1.

TABLE 1 R (in Compound vitro)

2.87

1.31

2.2 

1.43

2.44

1.44

1.12

1.14

1.20

1.22 The results show that the compounds according to the invention have the property of activating the TREK-1 channels.

EXAMPLE 9 Evaluation of the Analgesic Effect of the Compounds According to the Invention

The animals (mice weighing 15-20 g) are pretreated with the compound (10 mg/kg) or the carrier (control) 15 mins before injecting acetic acid (0.6% solution, 10 mL/kg) into the peritoneal cavity of the animal where it activates the nociceptors directly and/or causes an inflammation of the viscera (subdiaphragmatic organs) and subcutaneous (muscle wall) inflammation of the tissues. The number of induced abdominal cramps, determined for 15 mins after injection of acetic acid is used as a pain parameter. Pain inhibition (an analgesic effect) is determined by comparing the number of induced cramps in the presence and in the absence of the molecules.

The results are shown in Table 2.

TABLE 2 Inhibi- tion of pain in % Compound (in vivo)

50

51

22

31

26

34

45

55

43

27

The results show that the compounds according to the invention have significant pain inhibition properties. 

What is claimed is:
 1. A compound of formula (A1):

wherein: R represents:

Q represents —CN; X represents O, or —NH; T represents: a hydrogen atom; a phenyl group; a group

a cyclohexyl group; Q² represents O, or NH; or a pharmaceutically acceptable salt of said compound.
 2. The compound according to claim 1, wherein: Q represents —CN; Q² represents O, or NH X represents O or NH T represents: a hydrogen atom; a phenyl group; a group


3. The compound according to claim 1, wherein: Q² represents O; X represents O; T represents H.
 4. The compound according to claim 1 of formula (1b):

wherein Q², Q, X and T are as defined in claim
 1. 5. A method for treatment of pain comprising administering to a patient, a composition comprising a compound according to claim
 1. 6. A method for treatment of pain comprising administering to a patient, a composition comprising a compound according to claim
 2. 7. A method for treatment of pain comprising administering to a patient, a composition comprising a compound according to claim
 1. 8. A method for treatment of pain comprising administering to a patient, a composition comprising a compound according to claim
 3. 